Challenging behaviors are prevalent among adults with intellectual and developmental disabilities (IDD). In this review, we used the What Works Clearinghouse Standards (WWC) to evaluate the quality of 84 studies that aimed to treat the challenging behaviors of adults with IDD, ages 22 years and older, using a function-based intervention. Then, we summarized 43 studies that met the WWC Standards with or without reservations. Overall, we found self-injurious behaviors were the most commonly targeted behaviors and functional analyses were the most frequently used functional behavior assessment. Function-based interventions were effective across the majority of the included studies. We discuss the findings and provide directions for future research and implications for practice.